This invention relates to a process for producing peroxoniobic acid sol.
Much attention has been recently paid to functional ceramics suitable for use as a piezoelectric element, semiconductor, sensor, optoelectronics material, dielectric and the like. Niobium is one of the important components of such functional ceramics.
In the production of, for example, niobium-containing dielectric ceramics, it is desirable to use such a high quality powder material as is easy to sinter at low temperatures and is composed of perovskite phase only of high dielectric constant. Hence it is necessary to prepare a powder material with use of a niobium material which has a uniform, very small particle size and a narrow particle size distribution.
A niobium material has hitherto been produced by, for instance, admixing precipitates of such as hydroxides or carbonates of elements other than niobium with a slurry of commercially available niobium oxide or niobium hydroxide having a large and uneven particle size. This method, therefore, fails to provide a niobium powder material having a uniform and very small particle size.